1. Field of Invention
The present invention relates to a method and apparatus for allowing data to be passed between interconnected network devices. More specifically, the method and apparatus allows for the use of a specific protocol to allow for this communication between network devices.
2. Description of Related Art
As computer performance has increased in recent years, the demands on computer networks has significantly increased; faster computer processors and higher memory capabilities need networks with high bandwidth capabilities to enable high speed transfer of significant amounts of data. The well-known Ethernet technology, which is based upon numerous IEEE Ethernet standards, is one example of computer networking technology which has been able to be modified and improved to remain a viable computing technology. Based upon the Open Systems Interconnect (OSI) 7-layer reference model, network capabilities have grown through the development of repeaters, bridges, routers, and, more recently, “switches”, which operate with various types of communication media. Thickwire, thinwire, twisted pair, and optical fiber are examples of media which has been used for computer networks.
Switches, as they relate to computer networking and to Ethernet, are hardware-based devices which control the flow of data packets or cells based upon destination address information which is available in each packet. A properly designed and implemented switch should be capable of receiving a packet and switching the packet to an appropriate output port at what is referred to wirespeed or linespeed, which is the maximum speed capability of the particular network.
Basic ethernet wirespeed is up to 10 megabits per second, and Fast Ethernet is up to 100 megabits per second. The newest Ethernet is referred to as gigabit Ethernet, and is capable of transmitting data over a network at a rate of up to 1,000 megabits per second. As speed has increased, design constraints and design requirements have become more and more complex with respect to following appropriate design and protocol rules and providing a low cost, commercially viable solution. One such problem occurs when multiple switches are used to provide higher port densities. When such configurations of chips occur, additional logic must be employed to allow for data received at one of the interconnected switches to be forwarded to another of the interconnected switches.
As such, there is a need in the prior art for an efficient method and means for forwarding data between interconnected switches. In addition, there is a need for a standard that can be relied on to ensure the proper switching of data, including unicast, broadcast, layer 2 multicast, IP multicast, unknown unicast and control frames. Such a standard would need to be compatible with the existing forwarding hardware and allow for the transfer between switches to be transparent.